Heat exchange apparatus in refrigeration systems



June 10, 1947. L. B. M. BUCHANAN v 2,421,773

' HEAT EXCHANGE APPARATUS IN REFRIGERATION SYSTEMS I F ledpec. 29. 1 943 INVENTOR wrmsssas:

Lasus B.H.BUCHANAN M W,- I NWO E! Patented June 10, 1947 HEAT EXCHANGE APPARATUS IN REFRIGERATION SYSTEMS Leslie B. M. Buchanan, Springfield, Mass, as-

signor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania v I Application December 29, 1943, Serial No. 516,006

Claims. .l r This invention relates to refrigerating apparatus, more particularly to refrigerating appa ratus comprising a secondary refrigerant.

It is an object of the invention to provide an of the heat exchanger 35 of this invention. A tube 38 connects with an upper portion of the vessel. 34 and conducts the vaporized refrigerant from the vessel 34 to the casing [4 for recirculaimproved heat exchanger between the primary 5 tion. A quantity of lubricating oil 40 is located and the secondary refrigerating systems. in the casing l4 for lubricating the compressor Another object of the invention is to provide l0 and motor I! and for another purpose which an eflflcient heat exchanger between the primary will be described subsequently. The refrigerant .and the secondary refrigerating systems, which in the p im y system is od heat exchanger affords ready removal of one of fluoromethane) which refrigerant is miscible in the systems from the other. a and has an aflinity for mineral oil such as the A further object of the invention is to provide lubricating oil 40. a heat exchanger between an intermittently oper- The motor is energized f a source of power ated primary refrigerating system and a second- (not shown) through leads 42 and 44, and a therary refrigerating ystem, which heat exchanger mostatically operated switch 46 is located in the refrigerates the secondaiy system during and for lead The switch 4 s Controlled y a y p a short period after the operation of the primary bellows 43 which is operated by the pressure of system. a volatile liquid located in a bulb 50 positioned in These and o e Objects are effected by the heat exchange relationship with the evaporator invention as will be apparent from the following The v r pressure of the volatile liquid is description and claims taken in connection with Conducted a tube 52 0 the bellows T t e accompanying drawings, forming a part f thermostatic switch 46 causes the refrigerating this application, in which: apparatus consisting of the motor 10, the con- Fig. 1 is a sectional view of the heat exchanger denser 22, and the evaporator 0 to pe ate i of this invention taken on the line 1-1 of Fig. 2; as termittently to k p th temperature f the v p- Fig. 2 is an end elevation of the he t exchanger orator 30 substantially constant. This interof this invention; mittent operation comprises an operating cycle Fig. 3 is a diagrammatic illustration of refrigand a nolloperatihg Cycle which eaft l be erating apparatus including the heat exchanger referred as the Cycle and the yc shown in Figs. 1 and 2; and 30 The vessel 34 forms a header for the primary Fig. 4 is a sectional view similar to Fig. 1 of refrigerating System in which qu d and the a modification of a heat exchanger of this invanorous refrigerant of the y m para e and vention. also traps at least a portion of the refrigrant Referring specifically to the drawings, the pril q entering it so that the p t n nnot mary refrigerating system of the apparatus 35 escape through either of the tubes 32 or 38 during prises a compressor l0 and a motor I2 for drivthe Cycle- The Vessel 34 Comprises a cup ing the same, both the compressor lo and th 54, the lateral outer surface of which is cone motor 12 being located in a sealed casing l4. The ap d. The edge of the cup 5 s tu utcompressor includes an entrance port I6 com- Wardly to p v de a fl e d a ver 53 municating with theinterior of the casing l4 and 40 brazed to t flange 56 t seal t v l 34- an exhaust port communicating through a tube The secondary refrigerating system includes an 20 with the upper portion of a condenser 22. Revaporator 60 comprising a serpentine u e frigerant vapor is compressed and forced by the the ends of Which COmmllnicate through tubes ,-"compressor l0 intothe condenser 22 wherein it is 54 and 56 With the pp and lower portions, cooled and liquefied.- The condenser 22 is cooled spectively, Of a second Vessel 8 located n heat by a current of air drawn therethrough by a fan transfer relationship with the vessel 34. The ves- 1 24 driven by a motor 26. The condensed refrig- Sol 68 forms another part of the heat exchanger erant .passes through a capillary tube 23 to a of thisillvention.

primary evaporator 30 in which a portion of the The vessel 68 comprises a conical cup 10 similar liquid refrigerant vaporizes, in shape to the cup 54 and a cylindrical cup 12 The refrigerant flows from the evaporator 30 which is fitted over the conical cup 10. The into a vessel 34 through a. tube 32 connected to cylindrical cup 12 is provided with a flange l4 an'upper portion of the vessel 34. The remaining which is brazed to the flange 16 of the conical liquid of the refrigerant vaporizes in this vessel cup 10 to form a closed chamber. The vessel 34. The vessel 34 forms aheader and also a part 55 68 thus comprises a re-entrant portion consisting of the cup 10, the inner surface of which is in contact with the cup 54. v

The cover 58 and the flanges 56, 14 and I6 are perforated at diametrically opposite sides thereof and bolts 18 are passed through the perforations of the flanges to draw the cup 54 tightly into the cup I and into ,a wedging engagement therewith "to provide a good healconducting contact. The

cups 54 and lll are preferably formed of brass or other good thermal conductingmetal. The

secondary system contains a volatile refrigerant. The cup 54 may be provided with internal fins '80 and the cup 10 with external fins 82 as shown in Fig. 4 to increase the heat conduction between each of the cups 54 and HI and the respective refrigerant in contact with these cups.

Operation freezing temperature for the storage of unfrozen foods.

The portion of the refrigerant liquid of the primary system which is trapped in the vessel 34 during the on" cycle of the primary system will evaporate at least in part during the off cycle,

a part of the refrigerant vapor passing downwardly through the tube 38 into the casing 14 where a portion of it is absorbed by the lubricating oil 40. Another portion of the vaporized refrigerant from the vessel 34 passes through the tube 32 to the relatively colder evaporator 30 and condenses therein. The evaporation of the refrigerant in the vessel 34 during the off cycle of the refrigerant compressor I0 cools and condenses the refrigerant vapor in the vessel 68. The condensed refrigerant runs down the tube 66 and re-evaporates in and cools the secondary evaporator 60. This action tends to continue the cooling effect of the secondary evaporator 60 during the off cycle of the primary system.

Applicant's refrigerating apparatus comprises a secondary system which is separable from the primary system so that each system may be manufactured separately and be separately installed in a cabinet. This is efiected by the complete separability of the vessel 68 from the vessel 34. A coating of heavy machine oil is preferably placed on the outer surfaces of the cups 54 and Ill prior to their union together, which oil fills any voids between the two cups and aids in the transfer of heat.

It will be apparent from the above that this invention provides an improved heat exchanger between the primary and secondary refrigerating systems of a refrigerating apparatus. It will further be apparent that the heat exchanger affords separate manufacture of the primary and secondary refrigerating systems. It also provides for refrigerating the secondary system during the "oif periods of the primary system.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. In a heat exchanger for exchanging heat between two fluids, the combination of a substantially closed vessel having a portion of its walls formed into the shape of a cone and adapted to contain a fluid in contact with said wall portion, heat-conducting fins extending from the walls of said cone into the interior of said vessel, a second substantially closed vessel adapted to contain a fluid and having walls forming a re-entrant portion nesting snugly around the cone-shaped portion of the first-named vessel, and heat-conducting fins extending from the walls of said re-entrant portion into said second vessel.

2. Refrigerating apparatus comprising a primary system including a first evaporator, a second evaporator communicating with said first evaporator and forming a header, a casing containing a compressor and lubricating oil, a tube connecting said second evaporator with said casing, a condenser receiving compressed refrigerant from said compressor, a conduit connecting said condenser with said first evaporator, a thermostat for starting and stopping said compressor, and a volatile refrigerant in said primary system, said refrigerant having an aflinity for the oil in said casing, said refrigerating apparatus also including a secondary refrigerant circuit having a heat-absorbing portion and a.

heat-rejecting portion in intimate heat-exchange relationship with at least a portion of said second evaporator, said primary system being arranged to prevent drainage of liquid refrigerant from the heat-exchange portion of the second evaporator when said thermostat stops said compressor.

3. Refrigeratin apparatus comprising a primary system including a first evaporator, a second evaporator forming a header, a passageway connecting the first and second evaporators, a casing containing a compressor and lubricating oil, a tube connecting said second evaporator with said casing, a condenser receiving compressed refrigerant from said compressor, a conduit connecting said condenser with said first evaporator, a thermostat for starting and stopping said compressor, and a volatile refrigerant ing an afiinity for the oil in said casing, said refrigerating apparatus also including a secondary refrigerant circuit having a heat-absorbing portion and a heat-rejecting portion in intimate heat-exchange relationship with at least a portion of said second evaporator, said tube of the primary system communicating with an upper portion of said second evaporator, said passageway of the primary system being arranged to prevent drainage of refrigerant liquid from said second evaporator to said first evaporator when said thermostat stops said compressor.

4. Refrigerating apparatus comprising a primary system including a first evaporator, a second evaporator, a passageway connecting the first and second evaporators in series, a casing containing a compressor and lubricating oil, a

having a heat-absorbing portion and a heat-rejecting portion in intimate heat-exchange relationship with at least a portion of said second evaporator, said tube of the primary system communicating with an upper portion of said second evaporator, said passageway being arranged to prevent drainage of liquid refrigerant from said second evaporator to said first evaporator when said motor is stopped by said thermostat.

5. Refrigerating apparatus comprising a primary circuit including a first evaporator, a second evaporator forming a vessel, a passageway connecting said vessel with said first evaporator, means for supplying refrigerant liquid to said first evaporator and for withdrawing refrigerant vapor from an upper portion of said vessel, said means supplying sulficient refrigerant liquid to said first evaporator to flow through said passageway into said vessel, said means being adapted to be rendered active and inactive, said refrigerating apparatus also including a secondary refrigerating circuit having a heat-rejecting portion in vessel when said means is rendered inactive after a period of activity.

LESLIE B. M. BUCHANAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 516,206 Kellgren Mar. 13, 1894 536,354 Kohl Mar, 26, 1895 1,074,470 Sammis Sept. 30, 1913 1,926,384 Hull Sept. 19, 1933 2,073,741 Gibson Mar, 16, 1937 2,329,141 Scullen Sept. 7, 1943 2,233,414 Hubacker Mar. 4, 1941 2,336,418 Philipp Dec. 7, 1943 

